In the valve timing controller shown in US-2004-0206322A1, a planet gear mechanism varies a relative rotational phase between two rotors which rotate along with a crankshaft and a camshaft, whereby the valve timing is adjusted.
In this kind of valve timing controller, a gear provided in each rotor is engaged with the planet gear. Since a large reduction ratio can be obtained by compact design, it becomes suitable as a valve timing controller attached to an internal combustion engine.
The rotor of a crankshaft and the rotor of a camshaft change the relative rotational phase therebetween by performing relative rotation, while engaging each gear with the planet gear. Therefore, in order to make smooth the phase change by the planetary motion of a planet gear, it is necessary to secure the relative position precision in diameter direction between rotors by supporting one of rotors from its inner circumference by the other.
In the above valve timing controller, the rotor of the crankshaft is supported by the rotor of the camshaft accommodated therein. However, since the supporting section exists in the outer circumference of the gear provided in the rotor of the camshaft, the following problems will arise. That is, when the lubricant is supplied to the engaging part of the gear and the planet gear, the lubricant flows into a supporting portion by a centrifugal force, so that the lubricant flows outside from there and lubrication is deteriorated.
The present invention is made in view of the above matters, and it is an object of the preset invention to provide an electric valve timing controller which realizes a smooth operation and a high durability.